Household food-processing devices, also known as food processor, are used for mechanically processing foodstuffs. As an example, mechanical processing of the foodstuff refers to slicing, chopping, cutting, dicing, crushing, or grating. For different reasons, household food-processing devices have two or more units that are assembled or put together for operation of the household food-processing device. Besides storage aspects and cleaning issues, also the possibility to exchange a tool is thus provided. For example, a bowl is used as first unit, on top of which the so-called processing tool is arranged as second unit. A base unit is placed on top in order to transmit forces, for example, from a hand-blender providing the driving force, via a gearing mechanism to a drive shaft of the processing tool, finally operating the tool itself, for example a rotating knife or blade, or cutting or slicing plate or grating disk. For safety reasons, it is a requirement that unintended interaction of the user with a rotating tool should be prevented.